Amplifier of the magnetron type



May 30, 1950 w. c. BROWN AMPLIFIER 0F THE MAGNETRON TYPE 2 Sheets-Sheet. 1

Filed April 9, 1945 May 30, 1950 w. c. BRowN AMPLIFIER oF THE MAGNETRON TYPE Filed April 9, 1945 fr. RM n 0 Wg WFM/m. Ma. M Vf.. M

Patented May 30, 1950 i:(D- FFICfll 'AMPLIFIER 0F" THE MAGNE TRON TYPE l/illiam C. Brown, .Lincoln Mass., assignor to Raytheon Manutaeturing Company, Newton,

Mass., a ,corporation of Delaware Application Apriti), 1945,Se1'ia1Nm 587,249

lalaims. 1

My `present vinvention relates` to. `electron-discharge devices, andfmoreparticularly tolelectrondischarge '.devices tor .amplifying electrical `oscillations havinga wave .lengthf-iorhexample, of the order of a few centimeters, .or less.

Oneuof the objects of my.presentinventionlis to provide an electrondischargedeviceoi the general character indicated .which scapable` of handling extremely 4high-)frequency .energy .at highpowerlevels.

.Another .object of. my `present invention s..to provide VAan .electron-.discharge device 1having great sensitivity.

These,` and .other .objects of any.v present-.invention, :which willlbecome more apparent .as the detailed. description thereof progresses, are attained, :.brieiiy, in `theA following manner.:

:The electronfldischarge device` of. :my present invention is of the so-called magnetron ty-pe. It comprises, in general, a cathodestructuraean anode `.strncturaamtl means for .establishinga magnetic-field in a direction perpendicular tothe elcctronrpath. between. said cathode and .anode structures.

Said anode structure, preferably, includeslwhat I shall designate as pninflaryand secondary cavity resonators, and while. not necessarygl prefer that at leastl .one-.ow said. cavitvresonators comprise a plurality,` of anoderrnen'lbersf `eaclfifpair .of .adjacent f anode members, together with: thatwpcrtion ofthe .anode structureY lying therebetween, constituting a resonant line.`

elnoadditien to the `magnetic leldwalready referred; .to,. I. provide thel device :with` such electric fields, enacting with eachother .and 4said magnetic iield, that thelelectrons `emitted' by the cathode are` initially substantially uniformly` .distributed.` in .astream having `an. at leastpartially annular, cylindrical con-guratiomlsaid coasting magneticwand electricfieldsalso causing said stream` simultaneously to` rotate -onits own. axis, andgdritt along the samepastthe above-described cavity resonators.

I turther provide the device-with meansforintroducingi high-frequency :energy .intol the .primary cavity resonator,.,to excite. thesame andcorrespondingly `velocity vmodulate the electronstreamas said,` stream `passes said resonator.

Asafresuit of said modulation, said stream, in passing the secondary-cavity resonator, causes the.` :latter .to be. .excited into oscillation,` and. the highffrequency `energy Ygenerated; therein. `mayrloe extracted therefrom.

Now, the .primaryfcavity resonator'may .be considered la `'signal wave transmission enetwork functioning .as a buncherf and the-,secondary cen/ity` resonator.. a` .Similarnetwelk functioning as a catcherfso that when energyis introduced into` the primary cavity resonator at afloat-power level, the velocity modulation of the electr-onf streanigA brought Vabout as. above described, causes said energy ,ta be amplified in .the secondary -Cavity resonator.

;I vhave ioundthatlan,eleettenfdisehare'e device son made. iseeanahle of handling. extremelvfhiehfrequency, .energyat nien;` :newer levels. and .that swmanevice isicensiderably `more sensitive .than devieesfheretefore.made i0r..sm1ar purposes- In the f acc:oInn'an-vingv eneeieation I shanv describe, and in 1 the annexed .drawings show, en illustrative ernbcclirn` tottheeieetronfdiseharae dev-ice of my present.imentwn. .It is, ,ho ver; to .be Lcle.arly:undersood thatl do `not wishlto ,te limited t0 `the details herein Shown and desrbed for` purposes of illustration only., `inasmuch asl changeslztherein may. be. .made `Without the exercise of invention andwlthin the true spirit,4 and. Scopepf. the claims hereto appended.

said .drawings Eig. `1` is au longitudinal .,SQG- tional View takensubstantially .through-the center-.of anfelectrOmdiSQharge devicenmlde in accordance witlrtheprincinles otmy presentinven.- tion; and

Eig-2 isa transversesec-tional View taken-,mme line 2.72ct Eig; 1.

Referring now: more? ydetailrto the aforesaid illustrativa.embodiment.ofemy `present invention, andwith particulanveferenceeto. thedrawings il.- lustrating. the same; the-numeral 5f generallyidesignates `an..'eelctronsdischaree .deviceofl thesocalled magnetron type. Said device comprises, in. general, .an lanodesstructure: 6 a .cathode istituetura l, magnetic means iforestablishing .a mag--` netic field inadirection,perpendicularto the elec,- tnon path `b etween said `cathode .andancde strlmltures, and tuninganeans 9.

lin-.the device showr1, .thelanode structure: Shin cludes a paincflaxially aligned, abutting, cylin drical` bodiesf :liand: I Lfmadefof .highly conductive material, such as copper, and hermetically sealed at theirladjacentendslas ati1l2. Saidlbodies are provided, respectively, .-witli.. a. multiplicity, l .here shown as. eight.of anode omembers. preferably, in the-.for-.mof:interiorlyeextending,` radially-disposed vanes i3 `land.: 1:4,.eachpair of .adjacent Vanes, together with that. portion lof the correspondingcyli-ndrical tbody. lil .or,` i l" lying .therelbetween, constituting...a;-sectiontof, awavetrans--A mission l .netv.rork,.` more.` particularly, .a `resonant line Whose natural resonant:frequencyi is, asuis well known in the art to which my present invention relates, a function of the geometry of the physical elements making up the same. I shall further describe the anode members I3 and I4 when referring, in a later portion of this specilication, to the details of the tuning means 9.

The anode structure 6 is closed at its outer ends, for example, by end plates I5 and I5, with the respective junctions between the cylindrical bodies I0 and II, and said plates I5 and I6, hermetically sealed, as at I1 and I8. At the meeting ends of the cylindrical bodies I6 and II, the anode structure is provided with a centrallyapertured disk I9, which acts as a shield to divide said anode structure into, what I shall call, primary and secondary cavity resonators I4 and I3', the former including the anode members I4 and the latter including the anode members I3, said shield preventing coupling between said resonators.

The disk I9 has a short cylindrical section 20 secured in the central aperture thereof to provide an annular passage, about the cathode structure 1, between said primary and secondary cavity resonators.

The cathode structure 1, which is coaxial with the anode structure 6, includes a cathode sleeve 2|, conventionally made of nickel, or the like, provided with a reduced portion 22 extending from about the lower edges of the anode members I4 to a point corresponding to about one-third of the distance between the lower and upper edges of the anode members I3, measured from said lower edges. Said reduced portion 22 is, in turn, provided with a reduced portion 23 whose length, preferably, is a small fraction of the width of the anode members I4 and whose upper end, preferably, is on a line with the upper edges of said anode members I4, said reduced portion 23 being provided with a highly electron-emissive coating 24, for example, of the well known alkaline-earth metal oxide type.

In order properly to support the cathode structure 'I with respect to the anode structure 6, the sleeve 2| thereof may be reduced, as at 25, to t into an elongated, electrically-conductive tubular member 26 having, at its outer end, a ferrule 2l closed by a glass seal 28. Said seal, together with one or more glass beads 29 disposed within the tubular member 26, supports a lead-in conductor 30, which passes through said member 26 and has its upper end connected, as at 3l, to one terminal of a cathode-heating lament 32. The other terminal of said lament may be connected, as at 33, to the cathode sleeve 2|.

In order to convey current to the filament 32, the lead-in conductor 39 is connected by a conductor 34 to one terminal of a suitable source of E. M. F. (not shown), the other terminal of said source of E. M. F. being connected by a conductor 35 to a heat-dissipating member 36 fixed upon the lower end of the tubular member 26.

In order properly to insulate the cathode structure 'I from the anode structure 6, the tubular member 26 may have fixed thereto a cup-like bushing 31 sealed into one end of a glass tube 38, the other end of said glass tube having sealed therein a tubular bushing 39, in turn, secured to a tubular pole piece 40, constituting one of the components of the magnetic means 8.

Said pole piece 40 may be hermetically sealed, as at 4I, into the end plate I6, and be provided with a central bore`42 whereby the cathode structure 1 may enter the device.

Another tubular pole piece 43 may be hermetically sealed, as at 44, into the end plate I5, said pole piece and the pole piece 40 being fixed, for example, to the opposite ends of a horseshoe magnet (not shown), whereby an appropriate magnetic eld may be established, as previously indicated, in a direction perpendicular to the electron-path between the cathode structure I and anode structure 6.

If in a device as thus far described, the cathode structure I is suitably heated, and the anode structure 6 is made appropriately positive with respect to said cathode structure, for example, by means of a source 45 of E. M. F., electrical oscillations may be generated in the primary cavity resonator I4', said oscillations having a wave l length determined, primarily, by the distributed capacitance and inductance built into said resonator as a function of the geometry thereof, and more especially of the dimensions of the elements making up the resonant lines above referred to.

However, for the purposes of my present invention, such oscillations are undesirable, and in order to prevent them, I provide means for driving the electrons, emitted by the coating 24, away from the vicinity of the anode members I4 as soon after such emission as possible. To this end, I provide, for example, a short, cylindrical, repelling electrode 46, adapted to be supported, in the s-pace between the reduced portion 22 of the cath, ode structure and the anode members I4, at the end of a lead-in conductor 41, the latter passing out of the device and being supported in a glass seal 48, fused into a pipe 49 which is threaded and hermetically sealed into the end plate I6. The repelling electrode 46 is made appropriately negative with respect to the cathode structure 1, for example, by means of a suitable source 50 of E. M. F.

By the means just described, the electrons emitted by the cathode are urged out of the primary resonator I4. through the passage presented between said cathode and the cylindrical ection 20, and into the secondary cavity resona- However, for the purposes of my present in.- vention, it may not be desirable that such electrons be captured by the anode members I3 of said secondary cavity resonator. Therefore, I provide, for example, a short, cylindrical, collecting electrode 5I, adapted to be supported, adjacent the upper end of the cathode structure 1, and spaced from the inner ends of the anode members I3, by a lead-in conductor 52, said leadin conductor passing out of the device and being supported in a glass seal 53, fused into a pipe 54 which is threaded and hermetically sealed into the cylindrical body I0. The collecting electrode 5I is made appropriately positive with respect to the anode structure 6, by means, for example, of a suitable source 55 of E. M. F.

Now it will be noted that by means of the pole pieces 43 and 4I), a magnetic eld is established in a direction perpendicular to the electron-path between the cathode structure I and the anode members I4 of the primary cavity resonator I4. It will further be noted that an electric eld isv established between the cathode structure 'I and the anode structure 6; another electric eld is established between the cathode structure 'I and the repelling electrode 46; and still another electric eld is established between the anode structure 5 and the collecting electrode 5I.

These various elds extend in such directions, and areadjusted to beofsuch relative intensities,

that they ucoact "to linitiallylsubstantially=uniform f 1y` distribute*trie-electronsW emitted by tha cath-f ode in `an at* least# partially annular; cylindrical stream, and to' cause said streamsimultaneouslyf to Arotateu on itslfownaxis, and drift-axially-pastthe*4 anode-members- I 4-andf l 3 Aof the cavity resov Because-,5 as ali-earlyindicated, the electronsy emitted by the cathode are rapidly repelledlfromr the vicinity of f the primary cavity-resonator I4',

Said stream.

'Hcweven I now provide-afloop 56, which extends into the space `definediby anytwoLofr'ther.v`

anode members Il of the primary cavityresona'- tor i4', said loop being connected to-a conductor` Ellen-tering the device through `a glassrseal 58;

usedinto a pipe 59 which is threaded and hermetically-seaied into the cylindrical body Il, and when high-frequency energy isapplied to .thc

loop 55; said primaryicavity-resonator I4 is exe cited into oscillation.

Now, as the electron-stream, fashioned as above described, passes the elements making. up the primary cavityV resonator 14', some of th'ehelec-A trons are accelerated andothersf areretarded, whereby said stream becomes velocitymodulated in accordance with the high-frequency energy fedA into thedevice; and as said stream drifts past the elements `making up the secondary cavity resonal tor I3", it delivers energy to said-secondary cavity resonator a-nd, accordingly, excites the same into amplified osciliations.`

In order to extract power from the device, .I`

may, for example, introduce a loopfilinto the space defined by any twoA of the anode members I3`of the secondary cavity resonator i3', said loop l being connected to a conductor 6l supportedfinxa glass seal (notshown) fused into a pipefi-'l'which` is threaded and hermetically sealed into thecylindrical body It.

In order to assure the efficient absorptionofienergy` from the velocity modulated electronstream, I prefer that-the secondaryA cavityiiresonator I3? be tunable, and to this end, Iproceed asv follows:

Each anode `member i3. of said secondaryicavity-'resonator may be provided,A preferably, inbothA its upperiand lower edges,` adjacent itsinner end,

Without-away portions or. slotst, said slotsrbeing,A receptive of two pairs of concentric` conducting straps td and 65, and iiland the straps of each` I4i"n`1ay be slotted, asatit, .and provided with` two `pairs of straps B and lil; and 'H'and 12, said straps :presenting therebetween',capacitances enteringintothe determination of the natural resonant frequency of said primary cavity resonator` Inasmuch asl thestrapspf each'pair"tl'iereof` have a capacitance therebetween, they may be considered the plates of a capacitor, and by varyingthe rcapacitance between at least one lof.` said,` pairs, and introducing additional? capacitance 5in cavityV resonator: i3` is,` likewise, small.

\ 6l parallel-therewith; `tl1e.=c1evice cansbe `tum-ediand.; this imay `@bei accomplished as: follows: l

As statedg I .prefer-to^` apply the tuning-means to thesecondarycavity resonaton iffalone, alterf, ing= theafrequency thereof# until said-1 frequency matchesthefrequency at .which-the. primarycav-l ity1'rcsonator-` is ,L oscillatinga and,.i therefore, i the frequencyl oai-theV velocity modulation of: the L electron-stream, therebyrassuringmaximumfabsorption of energyfrom sad'electron-streamN A1plunger 13,1made1-Lof highly conductivefmaterial, such asflcoppen is sldably mountedv in thez. bore I4 fof theL tubular :pole-l piece L43, .theinnen end oft` said` plunger 1 being` cupped. to. provide. a

conducting annulus l5` whicinwhen movedpfor;

exampleli intermediate Jthestrapsrill and. 75,. con- I stitutes," together with Asaid straps, a: variable i ca-` pacitor: InL ordertovpermit theV conductor l 52,. whichfsupportsthe-collecting 4electrode 5l l at dts; inner.h end,2 to :pass out :of the device, theannulus s I5 may be provided withcan'elongated,slotfilri and orderi to Amaintaintheisoler/ice. air-tight,A I

provide an aperturedilflexiblefdiaphragmu ll, her-y metically sealed, at its periphery .13; .tothecylin-f `drical body I9 of the anode structurei; andsimilarlysealed, at il its/centrali aperture 1; l tol said plunger'lS.-

Thefintroduction lof-ly theV annulus 15 y into `,the e space` between-the straps-- 64(` and 55 -does two;` things; Firstfit reduces Athefieffective area of fthe, surfacesofl-saidl strapsebetween which the abovementioned'` capacitance exists, rbut `inasmuch c as this. capacitanceis` small :tor-begin with, 4the `overall effect on-the frequencyI of the secondary Second,l it'fforms; together-fwith said straps, two :capacitors; connected in series,` which Adid not, before, i einst-f` Inasmuch kasfthegapsbetween said ani nulus andsaidstrapsare small, the total capacitance; of-A ther` newlyvformedl capacitors is relatively large, and this capacitance,.added in parali lelwith what remains `ofthe-original capacitance, i has a considerable effect` upon the frequency of. thesecondarycavity resonator. Hence, even if` there isi considerable deviation between the naturalresonant frequency ofthe secondary cavity resonator and-the frequency of the oscillatinglienergy-'inathe primary cavity resonator,` which oscillating energy' it is desired4 to amplify, theffrequency-lof-lthe.secondary cavity resonator. can be'adjustedbylthe means `described to assure., the' most'reicient absorption of energy fromKV the velocity modulated electron-stream.

Theref remains to beN described the control mechanisrnpf'the tuningmeansi, by means of,` Whichiithe npenetration ofttheV annulus 'it` into the'` space intermediate the straps 64 and E5 may be varied;-

While not limited thereto', I. prefer to con-` structl such ltuning lcontrol nmeans v as follows Securedon the upper endfof the plunger `i3 is ai threaded bushing-180,? engageable in. a disk 8| i, whose'periphery maybe provided with aV-cut 82; constituting l af: ball-'bearing race. Surroundi ing saidra'celvisanother race comprised off two' cooperatingbevclled rings 83 `andrlt, theiring 83 being carried by adiskaand the ring 8'4 `being! pressed 'into cooperation .with'. said, ring 83 by :ani annular spring 86;- The races are,` receptive therebetween of fbearingr balls `87, and' the spring. fiisiaffxedl to Ythey diskibysa flat retaining,` ring 8 Stand 'bolts'` 89:L

Thezidi'skr 8 5 :iszmaintained against rotation v by: bengxbolted; asiat` 9I1to: wplaterilfl fixedat itsw4 center, to `the pole .f piece; 43,` the rplatert being.:,

provided with bearings (not shown) in which is journalled a shaft 92. Mounted upon the shaft 92 is a worm gear 93 engageable with a worm wheel 94 secured to the disk 8i by means of bolts 95. The shaft 92 is provided, at one end, with a pinion 96, whereby the same may be manually or otherwise rotated, slidably to move the plunger 13 with respect to the pole piece 43, and thus vary the capacitances between the straps Sli and 65,

and the annulus 'l5 and said straps.

This completes the description of the aforesaid illustrative embodiment of my present invention. It will be noted from all of the foregoing that I have provided an electron-discharge device of the magnetron type which is extremely sensitive and, therefore, capable of responding to a low-intensity input, and greatly amplifying the same. It will also be noted that the electrondischarge device of my present invention is capable of handling extremely high-frequency energy at high power levels.

Other advantages of my present invention will readily occur to those skilled in the art to which the same relates.

What is claimed is:

1. An electron-discharge device comprising; a cathode; an anode structure, spaced from said cathode, and including a pair of cavity resonators; said cathode and said anode structure being adapted to have an electric field established therebetween; means, adjacent said cathode and said anode structure, adapted to establish a magnetic field therebetween perpendicular to and cooperable with said electric field, thereby to distribute electrons emitted by said cathode substantially uniformly in a rotating, annular stream; means, adjacent said cathode and said anode structure, adapted to establish an electric eld substantially parallel to said magnetic eld and substantially perpendicular to said rstnamed electric field, thereby to cause said electron stream to drift axially past said cavity resonators; means, coupled to one of said cavity resonators, adapted to introduce high-frequency energy therein, whereby as said electron stream drifts past the same, it is accordingly velocity modulated, and as the velocity-modulated electron stream drifts past the other of said cavity resonators, the latter is thereby excited into oscillation; and means, coupled to said lastnamed cavity resonator, adapted to extract therefrom the high-frequency energy generated therein.

2. An electron-discharge device comprising: a cathode; an anode structure, spaced from said cathode, and including a pair of cavity resonators each of which comprises a pair of radially disposed anode members together with that portion of said anode structure lying therebetween; said cathode and said anode structure being adapted to have an electric field established therebetween; means, adjacent said cathode and said anode structure, adapted to establish a magnetic field therebetween perpendicular to and cooperable with said electric field, thereby to distribute electrons emitted by said cathode substantially uniformly in a rotating, annular stream; means, adjacent said cathode and said anode structure, adapted to establish an electric eld substantially parallel to said magnetic field and substantially perpendicular to said firstnamed electric field, thereby to cause said electron stream to drift axially past said cavity resonators; means, coupled to one of said cavity resonators, adapted to introduce high-frequency energy therein, whereby as said electron stream drifts past the same, it is accordingly velocity modulated, and as the velocity-modulated electron stream drifts past the other of said cavity resonators, the latter is thereby excited into oscillation; and means, coupled to said lastnained cavity resonator, adapted to extract therefrom the high-frequency energy generated therein.

3. An electron-discharge device comprising: a cathode; an anode structure, spaced from said cathode, and including a pair of cavity resonators; said cathode and said anode structure being adapted to have an electric field established therebetween; means, adjacent said cathode and said anode structure, adapted to establish a magnetic eld therebetween perpendicular to and cooperable with said electric field, thereby to distribute electrons emitted by said cathode substantially uniformly in a rotating, annular stream; means, adjacent said cathode and said anode structure, adapted to establish an electric field substantially parallel to said magnetic iield and substantially perpendicular to said first-named electric field, thereby to cause said electron stream to drift axially past said cavity resonators; means, coupled to one of said cavity resonators, adapted to introduce high-frequency energy therein, whereby as said electron stream drifts past the same, it is accordingly velocity modulated, and as the velocity-modulated electron stream drifts past the other of said cavity resonators, the latter is thereby excited into oscillation; means, supported adjacent said last-named cavity resonator and movable with respect thereto, adapted to tune the same to the frequency of said velocity modulation; and means, coupled to said last-named cavity resonator, adapted to extract therefrom the high-frequency energy generated therein.

Il. An electron-discharge device comprising: a cathode; an anode structure, spaced from said cathode, and including a pair of cavity resonators each of which comprises a pair of radially disposed anode members together with that portion of said anode structure lying therebetween; said cathode and said anode structure being adapted to have an electric iield established therebetween; means, adjacent said cathode and said anode structure, adapted to establish a magnetic field therebetween perpendicular to and cooperable with said electric eld, thereby to distribute electrons emitted by said cathode substantially uniformly in a rotating, annular stream; means, adjacent said cathode and said anode structure, adapted to establish an electric field substantially parallel to said magnetic field and substantially perpendicular to said first-named electric field, thereby to cause said electron stream to drift axially past said cavity resonators; means, coupled to one of said cavity resonators, adapted to introduce highfrequency energy therein, whereby as said electron stream drifts past the same, it is accordingly velocity modulated, and as the velocity-modulated electron stream drifts past the other of said cavity resonators, the latter is thereby excited into oscillation; means, supported adjacent said lastnamed cavity resonator and movable with respect thereto, adapted to tune the same to the frequency of said velocity modulation; and means,

coupled to said last-named cavity resonator,Y

adapted to extract therefrom the high-frequency energy generated therein.

5. An electron-discharge device comprising: a cathode; Van anode structure, spaced from said cathode, and including a pair of cavity resonators 39 each' of `which comprises I'a ipairof radially` disi posed A,allodez members: together-'With that-` portion sof said-anode structure lying therebetween; said cathode and said :anode structure being adapted [to have an electr-ic eld establishedtherebetween; i

`by as said electron stream `drifts past the same,tk

4it``is accordingly velocity modulated,` and as the velocity-modulated electron `stream `drifts past the other of said cavity resonators, the latter is nthereby excited into oscillation; a pair of conducting straps alternately contacting the successive` anode members of said last-named cavity resonator; a conducting member, supported adjacent said last-named cavity resonator and `movable withrespect to said conducting straps,

adapted to tune said: last-named cavity resonator i to the frequency oi said velocity modulation; end means, coupled to said last-named cavity resonator, adapted to extract therefrom the highfrequency energy generated therein.

6. An electron-discharge device comprising: av

cathode; an anode structure, spaced from said cathode, and .including primary ,and secondary ,cavity resonators; said cathode and said anode structure being .adapted `to have an electric eld established therebetween; means, adjacent said cathodeand saidanodestructure, adaptedto es- `tablish a magnetic eld therebetween, perpendicular to .and cooperable `with said electric field,

thereby todistribute electrons emitted by saidL cathode substantially .uniformlyin a rotating, annular stream;arepeller electrode, supported adjacent said primary cavity resonator, and adapted to establish yanY electric'field substantially A,parallel to said magneticV eld and substantially perpendicular to said first-named electric eld, thereby to cause said electron stream to drift axially past said primary and secondary cavity resonators; means, coupled to `said primary cavity resonator; adapted to introduce A high-'frequency I energy. therein, .whereby asA said `electron` stream .driftsvpast" the same, it `is vaccordingly velocity modulated, andas the velocityfmodulated electron stream drifts past the said secondary cavity resonator, the latter is thereby excited into oscillation; a collecting-electrode, supported adjacent said secondary cavity resonator, and adapted to establish an electric field between itself and said anode structure, thereby to collect the electrons drifing past said secondary cavity resonator, and means, coupled to said secondary cavity resonator, adapted to extract therefrom the high-frequency energy generated therein.

7. An electron-discharge device comprising: a cathode; an anode structure, spaced from said cathode, and including primary and secondary cavity resonators each of which comprises a pair of radially disposed anode members together with that portion of said anode structure lying therenetic eld and substantially perpendicularto `said iirst-named` electric iield, therebyto cause .being adapted .to have an electric field established therebetween; means, adjacent said cathodeand said anode-structure, adapted to establish a magnetic field Ytherebetween, perpendicular .to and cooperable 4with said electricleld, thereby to dis- .tr-ibute electrons emitted by said cathode substantially uniformly, in l a` rotating, annular stream;

a. repeller electrode, ,supported adjacent said `pri-- marycavity resonator,` and` adapted toslestablish an electric field substantially parallel to said magsaid-electron ,stream `to drift axially past-,said

, primary and `secondary cavity resonators; means,

`coupled. to saidfprimary cavity resonator, adapted 4to introduce high-frequency Aenergy ttherein,

.wherebyassaid l electron stream drifts f pastyk the same, it is accordingly -velocity modulatedfand as 1the velocity-modulated electron streamlidrif-ts past said secondary cavity resonator,` the latter-is l`thereby' excited 7into oseillationgva collecting `electrode, supported `adjacent said (secondary cavity resonator, and adapted `to Vestablish l an Aelectric -eld between itself and said anode structure, .therebyto -collectthe electrons drifting past said secondary lcavity` resonator; `and means, `coupled tosaid secondary cavityresonator, adapted toextracttherefrom the i highsfrequency energy `generatedtherein.

8. An electron-'discharge device `comprising'tH-,a cathode; an anode structure, spacedxiromvsaid cathode, and includingfprimary andsecondary cavityresonators; `said cathode and `said-anode structure being-adapted to have an electriclel'd establishedtherebetween; means, `adjacent said `cathode andsaid anode structure; adaptedtto establish aunagnetic eld therebetween, perpen- "dicularl to and cooperable with'said electric field, thereby' to distribute `electrons emitted by rsa-id cathode `substantially uniformly in arotating, Aannular "stream: a repeller ielectrode, supported adjacent `said 'primary cavity resonator, `and adapted to establish an electric field` substantially `parallel to said `magnetic'"field and substantially perpendicular ito said firstnamed `electric "field," thereby to cause said `electronstream to driitaxiallypast said `primaryand secondary cavity fresonators: means, coupled'to `said'prirnary:cavity resonator, adapted to intro- -ducel high-frequency energy therein, `whereby ,Las

said `electron strearndriftspast thesame, itlis accordingly velocity modulated, andasthe velocityamodulatedelectron stream drifts past said secondary cavity resonator, the latter is'thereby excitedinto oscillation; `a `collef'zting electrode, supported adjacent said `secondary cavity resonator, and adaptedto establish an eleotriofield between itself and said anode structure,` thereby to collect the electrons 'drifting pasty said ysec- 'ondary cavity resonator; means, supporteduadjacent said secondaryrtcavity resonator and 'movable with respect thereto, adapted to tune the same to the frequency of said velocity modulation; and means, coupled to said secondary cavity resonator, adapted to extract therefrom the high-frequency energy generated therein.

9. An electron-discharge device comprising: a cathode; an anode structure, spaced from said cathode, and including primary and secondary cavity resonators each of which comprises a pair of radially disposed anode members together with that portion of said anode structure lying therebetween; said cathode and said anode structure being adapted to have an electric eld esbetween; said cathode and said anode structure 75 tablished therebetween; means, adjacent said cathode and said anode structure, adapted to establish a magnetic field therebetween, perpendicular to and cooperable with said electric field, thereby to distribute electrons emitted by said cathode substantially uniformly in a rotating, an-

nnular stream;Y a repeller electrode, supported adjacent said primary cavity resonator, and adapted to establish an electric field substantially parallel to said magnetic iield and substantially perpendicular to said first-named electric field, thereby to cause said electron stream to drift axially past said primary and secondary cavity resonators; means, coupled to said primary cavity resonator, adapted to introduce highfrequency energy therein, whereby as said electron stream drifts past the same, it is accordingly velocity modulated, and as the velocity-modulated electron stream drifts past said secondary cavity resonator, the latter is thereby excited into oscillation; a collecting electrode, supported adjacent said secondary cavity resonator, and adapted to establish an electric field between Vitself and said anode structure, thereby to collect the electrons drifting past said secondary cavity resonator; means, supported adjacent said secondary cavity resonator and movable with respect thereto, adapted to tune the same to the frequency of said velocity modulation; and means, coupled to said secondary cavity resonator, adapted to extract therefrom the high-frequency 'energy generated therein.

tially uniformly in a rotating, annular stream; a

repeller electrode, supported adjacent said primary cavity resonator, and adapted to establish an electric field substantially parallel to said magnetic field and substantially perpendicular to said first-named electric eld, thereby to cause said electron stream to drift axially past said primary and secondary cavity resonators; means, coupled to said primary cavity resonator, adapted to introduce high-frequency energy therein, whereby as said electron stream drifts past the same, it is accordingly velocity modulated, and as the velocity-modulated electron stream drifts past said secondary cavity resonator, the latter is thereby excited into oscillation; a collecting electrode, supported adjacent said secondary cavity resonator, and adapted to establish an electric eld between itself and said anode structure, thereby to collect the electrons drifting past said secondary cavity resonator; a pair of conducting straps alternately contacting the successive anode members of said secondary cavity resonator; a conducting member, supported adjacent said secondary cavity resonator and movable with respect to said conducting straps, adapted to tune said secondary cavity resonator to the frequency of said velocity modulation; and means, coupled to said secondary cavity resonator, adapted to extract therefrom the high-frequency energy generated therein.

11. An electron-discharge device comprising: an anode structure; a cathode having an effective electron emitting surface, spaced from said anode; means for establishing an electric eld between said cathode and said anode; said anode comprising at least one signal wave transmission network, and having signal input and output means cooperating therewith; and means for establishing magnetic flux lines parallel to said emitting surface of said cathode.`

12. An electron-discharge device comprising: an anode structure; a cathode having an effective electron emitting surface, spaced from said anode; means for establishing an electric field between said cathode and said anode; said anode comprising at least one signal wave transmission network, and having signal input and output means cooperating therewith; and means for establishing magnetic flux lines perpendicular to a line normal to said emitting surface of said cathode.

13. An electron-discharge device comprising: an anode structure; a cathode having an effective electron emitting surface, spaced from said anode, said cathode being exposed to fields set up by high frequency energy supplied to said anode structure; means for establishing an electric field between said cathode and said anode; said anode comprising at least one signal wave transmission network, and having signal input and output means cooperating therewith; and means for establishing magnetic flux lines parallel to said emitting surface of said cathode.

WILLIAM C. BROWN.

REFERENCES CITED The following references are of record in the file of this patent:

UNITED STATES PATENTS Number Name Date 2,187,149 Fritz Jan. 16, 1940 2,295,315 Wolff Sept. 8, 1942 2,414,085 Hartman Jan. 14, 1947 FOREIGN PATENTS Number Country Date 509,102 Great Britain July 11, 1939 Disclaimer 2,509,419.-Wz'llam 0. Brown, Lincoln, Mass. AMPLIFIER 0F THE MAGNETRON Patent dated May 30, 1950. Disclaimer led Aug. 6, 1951, by the assignee, Raytheon Manufactwz'ng Company. Hereby enters this disclaimer to claims 1l, 12, and 13 of said patent.

[Ojoz'al Gazette September 11, 1.95 

